2.6. MRI assessment

Patients' MRI scans could stem from several scanners at their local radiological department, in accordance with the pragmatic setup. All were 1.5 Tesla. Sagittal and axial scans with running inclination adjustments according to each end‐plate surface were evaluated. T2‐weighted MRI scans were evaluated as long as the nerve roots could be readily identified, and the images were not compromised with severe artifacts.

MRI scans were assessed by Eval‐I (according to Supporting Information File 3), time wise far from the clinical exam, and thus without actual knowledge of the clinical data. The assessments were cross‐checked, after noting a conclusion, with the initial report of the examining radiologist.

All cervical nerve roots were considered in a patient's evaluation, and the root interpreted most severely affected was defined as the primary MRI root, defined by level and side; correspondingly regarding a secondary root. If the two roots could not be prioritized, we noticed them to be equal. In case of equality between more secondary roots, they were all designated as such.

Agreement between clinically and MRI designated roots were performed, calculated as % agreement. Cases were accepted if the side selected in the clinical examination was bilateral, and the MRI showed either left‐ or right‐sided pathology. Correspondingly, when the primary MRI pathology was bilateral, the left‐ or right‐sided clinical side was accepted.

For comparison between radiologists' and clinicians' MRI interpretations, a simplified system was used, illustrated in Table 4. The clinician was unbiased regarding the actual patient history, whereas the radiologist was informed about that.

Agreement analysis between the Eval‐I's and the radiologist's MRI assessments, where Eval‐I did the decision blinded to the clinical presentation